Base class variables are not accessible

[Prabakaran141]

Hi,

I just want to understand, why I'm getting below error in inheritance?

Error:
Traceback (most recent call last):
  File "inheritance.py", line 13, in <module>
    main()
  File "inheritance.py", line 10, in main
    print b_obj.aa
AttributeError: 'B' object has no attribute 'aa'

This is my python code

class A(object):
    def __init__(self):
        self.aa = None

class B(A):
    def __init__(self):
        self.bb = None
def main():
    b_obj = B()
    print b_obj.aa

if __name__ == '__main__':
    main()